


First Day Blues

by LittleFandomStories



Series: Little Hiro [1]
Category: Big Hero 6 (2014)
Genre: AU, Age Play, Infantilism, Non-Sexual Age Play, little!Hiro
Language: English
Status: Completed
Published: 2015-04-14
Updated: 2015-04-14
Packaged: 2018-03-22 20:36:53
Rating: Not Rated
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,314
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3742762
Author URL: https://archiveofourown.org/users/LittleFandomStories/pseuds/LittleFandomStories
Summary: <blockquote class="userstuff">
              <p>It's Hiro's first day of classes and he's giving Tadashi a hard time. A nervous little doesn't have an easy time getting back to big.</p>
            </blockquote>





	First Day Blues

Tadashi had spent the week preparing himself for today, he knew it was going to be rough and a complete uphill war of attrition. What had him gearing up for such a prolonged battle you ask? He was under five feet tall with messy black hair and was way too smart for his own good.

“C’mon Hiro, time to get up.”

The lump that was his younger brother made a groaning noise under the sheets as Tadashi climbed to his feet, stretching out his back and shaking out the numbness from where his brother had been laying on him.

“None of that, get up kid.” Tadashi kept his voice cheerful as he yanked the covers off Hiro.

If he didn’t keep his voice cheerful, Hiro would be grumpier than usual in an effort to spite him. Given that this was already a challenging day, he had to make things easier on him whenever he could. Hiro groaned and grasped for the blankets but Tadashi kept them out of reach.

“No time for that Hiro. Time to get up, it’s a big day.”

Tadashi tamped down on the frown at Hiro’s grumbles, he was certain his brother was calling him names but it was muffled by the pacifier taking up most of his mouth. Hiro was rubbing one of his eyes but the open was glaring at him something fierce, promising pain and revenge for waking him up. Taking advantage of Hiro sitting up, Tadashi scooped him and twirled around the room.

“It’s the first day of classes! Aren’t you excited!”

Hiro kicked and squirmed in response, tucking his head into Tadashi’s chest until he stopped twirling around the room. Tadashi smile down at him with his ever sunny disposition as he set the smaller boy down.

“It’s okay to be nervous Hiro. Everyone is nervous on their first day.”

“Not nervous.” Hiro snarled around the pacifier, crossing his arms.

Tadashi rolled his eyes, “Alright Mr. Not Nervous, arms up. We gotta get ready to go.”

He didn’t know what world he lived in that he expected Hiro to cooperate in the mood he was in. The fight to get the shirt, one of Tadashi’s old San Fransokyo Tech shirts, off took Tadashi tickling him and yanking one arm out at a time when Hiro finally squirmed.

“Whoa Hiro. Kinda glad we decided on a diaper instead of a pull-up last night huh?” Tadashi whistled once he wrangled the shirt away from Hiro.

“Shut up ‘dashi.” The red on Hiro’s face contrasted with the glare as he folded his arms again.

“Let’s go get you cleaned up and dressed then.”

Tadashi led his brother into their shared bathroom, pressing gently but firmly on his back when Hiro dug his heels. Tadashi never put diapers on Hiro, barring the small supply they kept for Hiro being sick or having a very bad day, because he worked hard on getting Hiro to use the potty and didn’t want to slide backwards and form a bad habit. Last night was an exception because he knew Hiro was nervous about classes and was prone to bed wetting when he was worked up. He had to be really nervous if he soaked that much, it was uncommon for Hiro.

“Can you sit on the potty for me Hiro?” Tadashi asked as he pulled the soaked diaper off and tossed it into the trash and handed Hiro a wipe.

Hiro’s head tilted five degrees to the left and his mouth drew into a thin line behind the pacifier. Tadashi gave an amused chuckle and took the wipe back and did it for Hiro before picking him up and depositing him on the toilet. Hiro was bound and determined to make this miserable for him. Keeping an eye on his brother, Tadashi stepped out to grab his and Hiro’s clothes he had set out the day before.

When he returned Hiro was standing defiantly in the middle of the bathroom and a quick glance at the toilet told Tadashi that he hadn’t gone at all.

“Oh no you don’t,” Tadashi set the clothes on the sink and placed Hiro back on the toilet, “You have to sit and go kid.”

Hiro rolled his eyes and sat there but as soon as Tadashi turned to start getting dressed, he was on his feet again. Tadashi, having just pulled his shirt for the day on, turned and put his brother back. The process repeated itself each time Tadashi looked away to pull on his clothes; he looked away, Hiro got up, Tadashi put him back.

With a sigh, Tadashi strode out the bathroom and returned moments later with a small red training potty covered in robot stickers in his hands. Hiro, who was standing, whined as Tadashi set it down on the ground.

“Your choice Hiro, use the big potty or your little one.”

Tadashi was hoping Hiro would use the big one, the little one was in their room for when Tadashi had to make Hiro go in emergency situations or for Hiro to use when he woke up in the night and couldn’t function enough to use the big one. His hoped were dashed when Hiro sat down on the little one.

It was slowly starting to sink in exactly how nervous Hiro actually was.

When Hiro was done, and had rinsed out his little potty, Tadashi cheered him on to get his clothes on by himself. Other than the typical struggle with the pull-up and putting on his shirt backwards, Hiro did a great job by himself. He even cracked a smile at the praise.

“C’mon Hiro, sit still so I can finish your hair.”

The progress went out the window when Hiro caught sight of the brush, it was the most hated part of his morning routine. Tadashi kept his brother still and brushed his hair, while brushing his teeth. It was with a purpose however.

“If you don’t sit still, I’m gonna get toothpaste in your hair.” Tadashi pointed out around his toothbrush.

How Hiro could discuss advanced robotics with his pacifier in his mouth Tadashi would never understand.

“No!” Hiro protested, shaking his head.

“Oops.”

“Tadashi!” Hiro whined as he quickly ran his fingers through his hair, searching for the offending toothpaste.

“Hey, I warned you. If you’d sit still it wouldn’t happen.”

Hiro harrumphed but sat still long enough for Tadashi to brush the mess into something resembling tamed and finish brushing his teeth. Hiro reluctantly allowed Tadashi to take his pacifier, watching carefully as it was placed into the red sanitation box he had made, and help Hiro through brushing his teeth.

A few minutes later they were sitting down and eating the pancakes and fruit Aunt Cass set in front of them. Hiro dug in, relishing in the amount of syrup he could drown them in, and Tadashi picked at the apples.

“So, you boys excited for classes today?” She asked, placing one of the pancakes on Tadashi’s plate before Hiro could eat them all.

Hiro made a face and Tadashi chuckled.

“Oh, Hiro’s so excited he was having a hard time being himself this morning.”

Aunt Cass frowned as she handed Hiro a napkin, “There’s no reason to be nervous Hiro.”

Hiro groaned as he lightly wiped his face off, “I’m not nervous. It’s just school. I don’t think I have anything new to learn.”

Aunt Cass and Tadashi shared a look as Hiro ignored them, shoving two of his fingers into his mouth. Tadashi pulled them out and guided him to the sink to wash them, on the way back Aunt Cass snagged the fork out of Tadashi’s mouth with a wink at Hiro. Tadashi made a face, not unlike Hiro’s, when Hiro giggled.

“Hey Hiro,” Aunt Cass put more apples on his plate and another pancake on Tadashi’s, “aren’t you going to work in the lab today?”

“Once my project gets approved.” Hiro mumbled, biting into the apple slice and arranging the others into a vague robotic shape.

“Don’t all your friends work in the same lab?”

Tadashi had to give it to Aunt Cass, she was better at this than he was. Hiro perked up at the idea of seeing the others, and being reminded that he knew people at school already. With Hiro distracted, and eating, Tadashi could focus on working his way through the food his Aunt had put in front of him. He didn’t usually eat in the morning, having to deal with Hiro and then bolt off, but when Aunt Cass caught him she always made sure he ate enough to eat.

After eating, and putting their plates in the sink, the brothers bid their Aunt good bye and climbed onto Tadashi’s scooter and were off. Like always, Hiro pressed his face into Tadashi’s back and the older Hamada brother took the time to think. He knew Hiro would be fine once he was settled and got to learning, that’s why he had Hiro petition to get himself into Advanced Robotic Theory rather than the usual intro class, but it didn’t stop him from worrying just a bit. He didn’t want Hiro to get engrossed and leak, or get distracted and shove a tool into his mouth.

Last thing he needed was another repeat of the Motor Grease incident.

Tadashi shook his head as he parked his bike in his spot outside the Robotics lab building. Hiro would be fine, he knew lab conduct. Hiro whined until Tadashi fixed his helmet hair, and held onto his brother’s lanyard as they walked to the building where Hiro’s first class was. Right before they entered the building, Hiro tugged they lanyard and yanked Tadashi into the shadow of the building before climbing up him and holding tight.

“Whoa, Hiro, thought you were a bit bigger now.” Tadashi commented as he patted his brother’s back.

“I’m nervous.” Hiro mumbled into Tadashi’s shirt, “Really, really, nervous.”

“I kind of got that.” Tadashi chuckled, not wincing when Hiro squeezed.

“Shut up ‘dashi.”

“Hey, you’re going to be fine. You have Advanced Robotic Theory, a lab, and an AI theory class. Those sound fun right?”

“Yeah.”

“And after those you’re done and you can come down to the lab and see everyone. We can even get lunch together.” Tadashi pressed on, “I’m sure someone will have something fun for you.”

“Go see Fred.” Hiro stated, lifting his head to look at his brother.

“Sure, we can go do that. Just us or do you want our friends to come along?”

Hiro shrugged and squirmed until Tadashi put him down, “I have to go to class…”

“I’ll walk you.”

Hiro followed Tadashi through the building, memorizing the twists and turns to get to the room. Entering the room, Hiro froze in the doorway. The room was huge, rows and rows of desks with a screen in the front of the room. A quick sweep showed Hiro where the projector was and he turned to bolt out the room, only to be blocked by his brother.

“Tadashi…”

“It’s okay. C’mon, back here is the best seat.”

Tadashi was glad he decided to follow Hiro to class, the kid almost bolted out of the small lecture hall. His hand was gently pushing Hiro up the steps until they reached the topmost row of seats and sat down. With a bit of prompting Hiro pulled out the notebook and pen, which Tadashi had Honey Lemon help him make so it tasted appalling to keep it out of Hiro’s mouth, and stuck his fingers in his mouth. With a sigh Tadashi let it be, a little bit of comfort wouldn’t hurt. As the minutes ticked by and more people filed in, Tadashi gently pulled Hiro’s fingers out and wiped them off.

“Tadashi, don’t you have class?” Hiro asked as he tugged his hand back and stuck his fingers back in.

“I’ll leave when I’m ready.” Tadashi pulled the fingers out again and cleaned them off.

Hiro grumbled to himself as Tadashi held his hand to keep the fingers out, but didn’t let go. He was still nervous and if he couldn’t have his fingers, Tadashi holding his hand would have to be enough. He couldn’t help but nervous, it was big and he was going to be alone and he wasn’t back in top gear fully. He was nervous all the way up until the professor started talking.

Tadashi smiled to himself as he watched Hiro’s face go from nervous to interested, to ‘ohmygod it’s something new.’ Hiro wrenched his hand free and started writing furiously across the page, his handwriting a meticulous scribble, and Tadashi slowly rose to his feet and made his way out the door.

Hiro was going to be just fine.

* * *

 

“So how is Hiro doing?”

Wasabi was the first to stick his head in as Tadashi plugged away at Baymax’s code, trying to fix one particular bug.

“He had a hard time this morning but once class started, he was all for it.”

Wasabi smiled, “Great. He should do fine, as long as he doesn’t get lost. Think I should send him a map of campus? I have some good ones.”

“Yeah, we’d both appreciate that.” Tadashi nodded, “We’re planning on going to go see Fred and eat later for lunch. You interested if he’s up for company?”

“Definitely, just let me know early.”

“Not a problem.”

Wasabi left, muttering to himself about maps of campus, and Tadashi kept working on the personality matrix. This bug was particularly challenging and Tadashi would be lying if he wasn’t enjoying it a little bit. Gogo had stopped by, merely looking in and nodding as if to make sure that he wasn’t fretting over anything other than work or that there wasn’t a upset Hiro hiding away in there. Tadashi passed along an invitation and got a positive response before resuming his work.

 

It was hours later, and one personality bug resolved, when Hiro rushed into the lab in a whirlwind of motion and energy.

“’Dashi, ‘Dashi, ‘DASHI! You won’t believe what I learned today! Did you know that you can-” Hiro descended into robotics and limits and new ways that he could make things.

Tadashi chuckled as he pulled the paper stick out of his brother’s mouth, “Sounds like your day was interesting.”

“Absolutely.” Hiro’s eyes wandered onto Tadashi’s screen and widened, “Whoa, that’s an AI. I saw those codes in that one class today.”

“Almost and AI. Baymax learns, but it’s not perfect yet.”

“Just let me take a look and I can-”

Hiro reached towards the screen but Tadashi yanked him back by his waistband.

“Not this time Hiro. You just started learning this code and this is my project.”

Hiro pouted, “But…”

“Not this time. So you liked your classes?”

“They are so amazing. Why didn’t you let me apply here sooner?!”

Tadashi chuckled, “You didn’t want to and I wasn’t going to force you.”

“Yeah, right. Anyway, so I had this idea for what my project is going to be.”

Tadashi listened intently, chiming in to help push his brother’s idea in the right direction. He hadn’t seen Hiro this happy in a while, especially not while actually being Hiro instead of little Hiro. Little Hiro was easy to get happy and excited.

“Alright, alright. Save some of it for later kid.” Tadashi cut Hiro off as he started stumbling over words.

Hiro harrumphed but climbed onto Tadashi’s lap, making himself comfortable. Tadashi wrapped one arm around him, hoping he’d calm down just a bit.

“So, did you stick any expensive lab equipment in your mouth yet?”

Tadashi could almost hear the eye roll, Gogo would have been proud of that one, “No, I didn’t. I even kept my fingers out.”

Tadashi inspected the fingers as Hiro held them out and found no new signs of them having been in Hiro’s mouth.

“Wow, good job kid. I think that’s a first for you.”

Hiro made a face, “I keep my fingers out.”

“You keep a pacifier in instead. You had nothing all day, it’s impressive.” Tadashi reached into one of his drawers, it was labeled Hiro in his own personal code, and pulled out a sheet of stickers.

Hiro’s face lit up, “I get a sticker?!”

It was the simple things, Tadashi chuckled to himself.

“Yes, you get a sticker. You kept stuff out of your mouth for all of your classes, that’s more than I can say.”

Hiro snagged the sheet and peeled one off, it was motorcycle this time, before sticking it on his shirt. After a moment he peeled another one off, this one a ninja, and stuck it on Tadashi’s shirt.

“For helping me today.”

“Awwwww. Come here you!”

Hiro squealed as Tadashi rained kisses down on him, squirming to get away. When Tadashi was done, they were both a little out of breath and Hiro as perched on the workbench away from Tadashi, eyeing him warily.

“Hiro, if we’re going to go eat something I’ve got to check you.”

Hiro eyed him, “No more kissy monster?”

“Promise.”

“No tickle monster?”

“No tickle monster.”

“No uncontrollable airplane?”

Tadashi chuckled, “No Hiro. Now come here.”

Hiro hopped down and made his way over, letting Tadashi unzip his pants. Hiro was a bit embarrassed that he was wet but Tadashi wasn’t surprised. The easiest thing for Hiro to forget was to use the bathroom and considering the day the younger Hamada was having, it was the most predictable outcome.

“Alright then. Let’s get this off and you go sit on the potty.”

How Tadashi managed to get a lab with a toilet in a side room he would never know, but with his brother around it was a great thing. While Hiro kicked his shoes off, Tadashi tore the sides of the pull up and helped him step out of the pool of shorts.

Tadashi blinked as Hiro sat and didn’t get up, kicking his feet and whistling to himself. It had to be a good day for Hiro to not fight like that and that was enough to bring a smile to his face.

There was a shutter-click of a camera and a giggle, which was enough to bring some color to Tadashi’s face.

“Never seen someone smile about a wet diaper before. There something special about it?” Honey Lemon asked innocently, tucking her phone away.

Tadashi tossed the pull up in the trash, “Not quite. I was lost in thought.”

“Have to be careful with that. How’d Hiro’s first day go?”

Before Tadashi could answer, Hiro bolted out the bathroom with a shout of “Aunt Honey!” and wrapped his arms around her as he chattered away about his day.

“Kid, rule 15.” Tadashi sighed, pinching the bridge of his nose.

Hiro froze mid-sentence, talking about this new robot he wanted to build, and turned red. Honey smiled politely and averted her eyes as Tadashi helped the embarrassed Hiro get into a fresh pull up and his clothes back on. It wasn’t the first time Hiro had done something like this, so Honey wasn’t as mortified as she had been the first time.

“So what’s your sticker for Hiro?” She asked once he was dressed again.

“Didn’t put anything in my mouth.” Hiro beamed proudly, “It’s a motorcycle and has mag suspension like Gogo’s bike and a jet engine.”

Tadashi shook his head ad mouthed ‘sorry’ to Honey as Hiro rattled off the specs to his motorcycle, that genius imagination got the best of him when he got like this. Honey shrugged and made a suggestion about fuel composition and the two were off arguing what the best chemical makeup would be. Tadashi half turned to his screen and toyed with code, those two would be at it for a while.

At least Hiro had a good day.


End file.
